Andrographis paniculata Nees is an annual herbaceous plant which belongs to the family Acanthaceae. It is commonly known as kalmegh, is found in the plains of India, China, Pakistan, Sri Lanka and South Asia and is native to India and Sri Lanka. Kalmegh is known to be the {\textquotedblleft}king of bitters{\textquotedblright} though it is of small size and it also has a similar appearance and taste as that of the Neem plant. It is one of the widely used effective medicinal plants in the world. All parts of this plant are used to extract the potential phytochemical, but the composition of phytoconstituents mostly differs from one part to another in a season, place and time of harvest. It is a traditional medicinal plant widely used in the treatment of anti-inflammatory, anti-bacterial, anti-oxidant, hepatoprotective, hematocidal, anti-HIV, anti-cancer, anti-diabetic, arthritis, rheumatism, cough, cold, multiple sclerosis, depression, diarrhoea, dysentery, candida, fevers, herpes, leprosy, malaria, jaundice, tuberculosis and several infectious diseases ranging from malaria to dysentery. The plant is widely used in Ayurvedic and homeopathic system of medicine. The medicinal value of this plant is due to the active ingredients via andrographolide and neoandrographolide, which are derivative of diterpinoids. It prevents oxidative damage and inhibits binding of toxic metabolite to DNA.